Process of manufacture of cellulose esters or ethers in a solvent



Dec. 22, 1925- 1,566,398

N. B. GRILLET PROCESS OF MANUFACTURE OF CELLULOSE ESTERS OH ETHERS IN A SOLVENT Filed Nov. 22, 1924 I N V'ENTOR; I Nico/as 5no/'7" Gri/lzf A T T O R N EY Patented Dec. 22, p 1925.

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Application-lied Iovember an, 1924. Serial Io. 751,455.

' To all whom it may concern:

, Be it known that I, NIoonAs BENOIT Gnu.-

vLa'r, residing at Neuilly, Seine, France, a

citizen of the Republic ofv France, have invented certain new and useful Improvements in Processes of Manufacture of Cellulose Esters or Ethers in a Solvent, of which the following is a specification.

It is known that, in the etherification and esterification of cellulose in a liquid medium, it is not sufiicient to treat the cellulose by just the quantity of reagents necessary for the reaction, for if such was-the case, a'

very thick product would be obtained, which it would be when energetic stirring is absolutely necessary, not only to allow of the heat generated by the reaction being properly dissipated, but also to ensure that the reaction is performed in the whole mass in a manner as homogeneous as possible.

In order to obvi te this drawback, in all the processes used for the etherification and the esterification' of cellulose in a liquid medium, a pro ortionally large amount of a diluent suitable for use is added to the reacting mass, for instance, six times the weight of the cellulose acted upon, or even more. g

This diluent may consist of an excess of I the necessary reagents, but, in the processes usually adopted, and to which the present invention refers more specially, the ether orester of the cellulose manufactured is selected as a diluent. In this manner, the mass under treatment is, as a matter of feet, thick at the beginning of the reaction, but, as the latter proceeds, the mass becomes more 'fluid, to become finally a more or less viscous fluid.

Unless a very large roportional amount of solvent is used, whic would be costly, it is nevertheless necessary, because of .the 'first (thick) phase of the reaction, to use apparatus provided with very powerful stirrin dev1ces, for instance, mixers of the e erner-Pfleiderer (Chimie et Industrie, 1920, Vol. 1, page 600).

These apparatus are costlyand absorb much power. Unless their mixing members are of unusually large dimensions, they can only deal in one operation with relatively small quantities of cellulose, 200 to 300 kilogrammes, for example. Finally, the use of ractically impossible to stir,

a solvent of mixers or of baflles used in connection therewith entails the resence in the apparatus of corners with de 'cient stirring where cellulose accumulates' whichescapes more 'or less completel from the reaction, and 80118 the Applicant has discovered that all these an economy of solvent, by conducting the esterification and fletherification of cellulose in rotary apparatus, with or without in ternal balls, rolls, rollers, or the'like, in order to enhance the internal stirring and preferably driven from their periphery, so that they do not contain inside any shaft or other supportin or driving members.

' In the rawingsaccompanying and .form

ing? part of this specification 1g. 1 is a longitudinal sectional view of I a form of apparatus constructed in accordance with the present invention; and

Fig. 2 is a transverse section thereof.

Referring. to the drawings a is a cylindrical container provided with peripheral rails 12 b resting on rollers c c and driven round by a. toothed wheel d engaging a peripheral .rack e. The container is cooled or heated by means of the sprayer f, A

manhole g and a drainage aperture h are provided, and also 'samphng pipes 10 k.

Apparatus such as that above described are free from any corner where cellulose could escape from the reaction.

It is, on the other hand, practically easy to give tovsuch a paratus such large dimensions as may be esired, for instance, ten 'or twenty meters cubed or even more, so as to treat in one'operation 1,000 kilogrammes of cellulose or more. In this way installation costs, as. well as the power consumed and the cost of manufacture and of supervision, are reduced. Moreover, large amounts of cellulose derivatives, perfectly. homoeneous, are thus obtained, which isof great lmportance for their ultimate use, for in stance, for the manufacture of threads, films or plastic bodies. Such a result could only be obtained ing fications or esterifications.

Finally, it is possible to reduce very noticeable proportions the quantity of solvent employed, for example, to 2 or 3 times very imperfectly before, by mix only the weight of cellulose, while nevertheroducts of several independent etheriless obtaining a regular and homogeneous reaction. 7 V

It is understood that one can 've to the rotary apparatus forming the ob 'ect of the invention anyform suitable in view of the result sought, 0 lindrical, spherical or other. For example, t ey may have the shape of a cylinder, with a horizontal or oblique axis, rolling on its side upon rollers, or by means of gearings or of any other suitable devices. The internal stirring will be enhanced by selecting rather a flat shape and a large diameter.

- Moreover, by varying the speed of rotation,

' any suitable process.

as well as the number and weight of the balls, rolls, rollers and the like, m, introduced into the apparatus, it will be understood that a sufiicient stirring can be obtained in all cases.- The apparatus are cooled externally by For instance, their lower portion may dip into a trough filled with cold water or brine, or else their walls may be sprayed, by means of suitably disposed perforated pipes, with cold water or brine, or both methods may be used simultaneously. Naturally the form of the apparatus, its speed of rotation, and the amount and temperature of the cooling water or brine will be chosen so as to ensure as much as may be needed the dissipation of the heat generated during the reaction. On the contrary, by substituting hot for cold water, the same arrangement may be utilized to supply heat to the reacting mass. Finally, the apparatus will be provided with any accessory or desired devices, such as inspection windows, manholes, or charging openings; sampling arrangements, drainage cocks, etc., the installation of which does not present any difficulty.

Particularly, the charging may take place in a convenient manner by a manhole provided in the side of the apparatus and brought to the top to the level of a charging platform. The emptying may be performed by gravitation through the same aperture or by a special cock, brought to the lowest position underneath, after, if necessary, removing the cooling trough. It can also take place by decanting, by means of a removable pipe introduced inside the apparatus by any aperture brought to the top.

What I claim and desire to secure by Letters Patent is 4 1. A process of esterifying cellulose, which consists in executing t e reaction in the presence of a liquid solvent of the desired product in a comparatively large closed vessel, and rotating said vessel thereby to agitate the mixture.

2. A process of esterifying cellulose, which consists in executing the reaction in the presence of a liquid solvent of the desired product in a comparatively large closed vessel, placing in said vessel loose members, and rotating said vessel thereby to cause said members to roll around and agitate the mixture.

3. A process of esteri ing cellulose,'which consists in executing t e reaction in the presence of a liquid solvent of the desired product in a comparatively lar e closed vessel, rotating "said vessel there y to agitate the mixture, and cooling the vessel during rotation. s.

4. A process of esterifying cellulose, which consists in executing the reaction in the presence of a liquid solvent of the desired product, the proportions by weight of said solvent to the cellulose being approximately 2 to 3, in a comparatively large closed vessel, and rotating said vessel thereby to agitate the mixture.

5. A process of esterifying cellulose, which consists in executing the reaction in the presence of a liquid solvent of the desired product, the proportions by weight of the solvent to the cellulose being up roximately 2 to 3, in a closed Vessel in sufiibient quantity to occupy 30 to per cent of the capacity of the vessel, and rotating the vessel-thereby to agitate the mixture.

6. A process of acetylating cellulose, which consists in executing thereaction in the presence of a liquid solvent of the desired product, the proportions byweight of the solvent to the cellulose. being approximately 2 to 3, in a closed vessel in suflicient quantity to occupy 30 to 50 per cent of the capacity of the vessel, and rotating the ves sel, thereby to agitate the mixture.

In testimony-whereof I afiix my signature.

NICOLAS 'BENOIT GRILLET- 

